The program calling this method considers itself as an intermediate step in the message delivery process; it therefore leaves a resent group of header fields as trace.

When a message is received, the Mail Transfer Agent (MTA) adds a Received field to the header. As %options, you may specify lines which are added to the resent group of that received field. Resent-* is prepended before the field-names automatically, unless already present.

If you are planning to change the body of a bounce message, don't! Bounced messages have the same message-id as the original message, and therefore should have the same content (message-ids are universally unique). If you still insist, use Mail::Message::body().

The message bounce() method forwards a received message off to someone else without modification; you must specified it's new destination. If you have the urge not to specify any destination, you probably are looking for reply(). When you wish to modify the content, use forward().